1. Field of the Invention
This invention relates to a digital computer system having a store queue facility. More particularly, it concerns a store queue facility wherein digital words are assembled within the store queue prior to storage in a system memory or the like.
2. Description of Related Art
In the early days of digital computing, reading from and writing to the high speed memory, as well as peripheral apparatus, was done directly. Reading from and writing to peripheral equipment was so extremely slow compared to the computer operational speeds that it soon became evident that buffer registers could be employed to rapidly accept the information being read from or written to peripheral equipment. The buffer registers then could be separately emptied into either the peripheral equipment in the case of a write, or into the computer in the case of a read.
It was later determined that buffering of write operations to the computer main memory is desirable because there are many more read operations than write operations in the ordinary program. Therefore, buffering the write operations avoids interference with the read operations and consequently provides much more useful computing time. The write buffer is commonly known as a store queue.
The store queue facility then is employed to decouple memory write time from the processor store cycle time. That is, the store queue acts as an intermediate store between the processor and the memory. This implementation gives priority to memory reads which improves system performance.
This invention involves use of the store queue, but greatly enhances this facility by assembling one or more bytes (8 bits) into a single word in the store queue prior to writing into the memory or other addressable unit.